This application requests five additional years of support for training in population research at the Center for Demography and Ecology, University of Wisconsin-Madison. Although we have expanded our interdisciplinary activities and the breadth of our training, we are requesting the same number of predoctoral (8) and postdoctoral (1) stipends. The Center for Demography and Ecology has for nearly 50 years offered a world-class program of training in population science. Its graduates are among the most renowned demographers and population scientists. The training program is based on four critical ingredients: outstanding and diverse faculty conducting innovative research; capable and committed graduate students; high-quality resources for faculty and student research and study; and a well-designed and fully implemented curriculum combining course work and research experience. Since 2009 CDE has been an independent unit in the College of Letters & Science, raising its visibility and facilitating the development of intellectual linkages across campus. New and stronger ties across departments and disciplines enhance students' interdisciplinary training experiences. The international components of CDE's research portfolio have grown extensively in the past five years, producing a diverse set of international projects and research networks through which students can develop their own international research agenda. The 45 members of the CDE training faculty offer a rich curriculum and extraordinary opportunities for students to participate on a wide variety of research projects. Research resources provided to students from CDE's infrastructure grant, individual grants, and university support are outstanding. Together with a demanding curriculum and an intensive apprenticeship system, CDE's human and material resources produce one of the best available environments for pre- and postdoctoral training in population research.